Biometric devices are increasingly common in computer or network security applications, financial applications, and surveillance applications. Biometric devices detect or image a unique physical or behavioral trait of a person, providing biometric data that can reliably identify the person. For example, a fingerprint includes a unique pattern of ridges and valleys that can be imaged by a fingerprint sensor. The image of the fingerprint, or the unique characteristics of the fingerprint, is compared to previously captured reference data, such as a reference fingerprint image. The identity of the person is obtained or verified when the newly captured fingerprint image matches the reference fingerprint image.
Typically, a user has to enroll reference biometric data that will be used for authentication. For example, a user may have to enroll one or more fingerprints before he or she can use the fingerprints for authentication. During the enrollment process, an image of each fingerprint that will be used for authentication is acquired and extracted features of the fingerprint are stored in a memory. The extracted features can then be used as reference fingerprint data during the authentication process. In some situations, however, the user may have to scan a fingerprint a number of times to obtain a fingerprint image that has adequate fingerprint coverage and an acceptable resolution. For example, a user may move or shift the finger during image capture, which can produce a blurry fingerprint image. Alternatively, contaminants such as dirt and water may be present on the finger being scanned, which can adversely affect the fingerprint image and/or the ability of the fingerprint sensor to obtain a fingerprint image. These and other challenges can be exacerbated when a user has to enroll multiple fingerprints.
Even after enrolling the biometric data and using a biometric sensing device to authenticate the identity of a user, a user may still be required to enter a password or pin when the user wants to access an application, a website, or another device. Thus, a user may be required to repeatedly enter pins or passwords when the user launches or switches applications, functions, and websites.